Check out the blackboard. That box on the left has all of the information you need to know about one element. It tells you the mass of one atom, how many pieces are inside, and where it should be placed on the periodic table.

In the next section we're going to cover electron orbitals or electron shells. This may be a new topic to some of you.

Electrons In The Shells

Take a look at the picture below. Each of those colored balls is an electron. In an atom, the electrons spin around the center, also called the nucleus. The electrons like to be in separate shells/orbitals. Shell number one can only hold 2 electrons, shell two can hold 8, and for the first eighteen elements shell three can hold a maximum of eight electrons. As you learn about elements with more than eighteen electrons you will find that shell three can hold more than eight. Once one shell is full, the next electron that is added has to move to the next shell.

So... for the element of LITHIUM, you already know that the atomic number tells you the number of electrons. That means there are 3 electrons in a lithium atom. Looking at the picture, you can see there are two electrons in shell one and only one in shell two.

Examples of Compounds with Lithium

Lithium Oxide

Two lithium (Li) atoms can bond with one oxygen (O) atom, making the formula Li2O. Oxygen likes to have two additional electrons to make it happy. Each lithium atom provides one. You can see that the oxygen atom has eight electrons (6 of its own, and one from each lithium), and the two lithium atoms have two electrons each.

Lithium Fluoride

One lithium atom can combine with one fluorine (F) atom. Together, they make the formula LiF. Fluorine has seven electrons of it's own. Lithium gives up its one electron to make both atoms happy. So the fluorine atom has eight electrons, and a filled outer shell.